U.S. patent number 10,184,958 [Application Number 15/609,567] was granted by the patent office on 2019-01-22 for current sensor devices and methods.
This patent grant is currently assigned to Infineon Technologies AG. The grantee listed for this patent is Infineon Technologies AG. Invention is credited to Udo Ausserlechner.
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United States Patent |
10,184,958 |
Ausserlechner |
January 22, 2019 |
Current sensor devices and methods
Abstract
Devices and methods associated with current measurements are
provided. A current in a conductor portion may be measured by a
current sensing element. An output signal indicative of the current
may be generated based on the measured current and information
regarding a current path.
Inventors: |
Ausserlechner; Udo (Villach,
AT) |
Applicant: |
Name |
City |
State |
Country |
Type |
Infineon Technologies AG |
Neubiberg |
N/A |
DE |
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Assignee: |
Infineon Technologies AG
(Neubiberg, DE)
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Family
ID: |
54261907 |
Appl.
No.: |
15/609,567 |
Filed: |
May 31, 2017 |
Prior Publication Data
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Document
Identifier |
Publication Date |
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US 20170261535 A1 |
Sep 14, 2017 |
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Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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14261975 |
Jun 6, 2017 |
9671433 |
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
G01R
15/207 (20130101); G01R 15/18 (20130101); G01R
1/203 (20130101); G01R 19/0092 (20130101); H01L
2924/0002 (20130101); H01L 23/49541 (20130101); G01R
35/005 (20130101); H01L 2924/0002 (20130101); H01L
2924/00 (20130101) |
Current International
Class: |
G01R
15/18 (20060101); G01R 19/00 (20060101); G01R
1/20 (20060101); G01R 15/20 (20060101); G01R
35/00 (20060101); H01L 23/495 (20060101) |
Field of
Search: |
;324/118 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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10333089 |
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Mar 2005 |
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DE |
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102013100156 |
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Jul 2013 |
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DE |
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Primary Examiner: Hollington; Jermele M
Assistant Examiner: McAndrew; Christopher
Attorney, Agent or Firm: Schiff Hardin LLP
Claims
What is claimed is:
1. A current sensor device, comprising: a current sensing element
adapted to sense a current in a conductor portion, and an output
adapted to output a signal indicative of the current in the
conductor portion based on an output of the current sensing element
and information regarding a current path outside of the conductor
portion, wherein the output is adapted to correct an output value
of the current sensing element based on the information regarding
the current path.
2. The device of claim 1, wherein the information regarding a
current path comprises information regarding the polarity of the
current.
3. The device of claim 1, wherein the information regarding the
current path comprises information indicating an approximate
magnitude of the current.
4. The current sensor device of claim 1, wherein the current sensor
device comprises a memory to store information regarding an
adjustment depending on the information.
5. The current sensor device of claim 1, wherein the output is
adapted to obtain the information regarding the current path based
on a preliminary sensing of the current by the current sensing
element, wherein the preliminary sensing is prior to actual
sensing.
6. The current sensor device of claim 1, wherein the conductor
portion is housed in a common package with at least one of the
current sensing element or the output.
7. The current sensor device of claim 1, wherein a length of a
current path through the conductor portion is less than 50 mm.
8. The current sensor device of claim 1, wherein the current
sensing element comprises a shunt-based current sensing
element.
9. The current sensor device of claim 1, wherein the current
sensing element comprises a magnetic field based current sensing
element.
10. The device of claim 1, wherein the device is adapted to measure
currents of up to at least 20 A.
11. A method, comprising: obtaining information regarding a current
path, measuring, by a current sensing element, a current in a
conductor portion, and generating, by a corrector, an output signal
based on the information regarding the current path and the
measured current, wherein generating the output signal comprises
correcting the measured current based on the current path
information and a path the current takes outside the conductor
portion.
12. The method of claim 11, wherein obtaining the current path
information comprises performing a preliminary measurement to
obtain a polarity of the current.
13. The method of claim 11, wherein obtaining the current path
information comprises performing a preliminary measurement to
obtain an approximate magnitude of the current, wherein the
preliminary measurement is prior to an actual measurement.
14. The method of claim 11, wherein correcting the measured current
comprises correcting the measured current by less than 10% of the
measured current.
15. The method of claim 11, further comprising calibrating the
correction to account for an environment of the conductor
portion.
16. The method of claim 11, wherein measuring the current comprises
measuring a magnetic field caused by the current.
17. The method of claim 11, wherein measuring the current comprises
measuring a voltage drop caused by the current.
Description
TECHNICAL FIELD
The present application relates to current sensor devices and to
corresponding methods.
BACKGROUND
Current sensors are used in various applications to measure an
electric current flowing through a conductor, for example a metal
conductor or other type of conductor. Various types of current
sensors are commonly employed in various applications. A first type
of current sensor comprises magnetic current sensors, which measure
a magnetic field generated by an electric current. Such a
measurement does not need a galvanic coupling of a sensor circuit
and the measured current. Magnetic current sensors may be coreless
magnetic current sensors, where a magnetic flux generated by the
current is not guided by permeable magnetic parts such as a soft
magnetic transformer core, or magnetic current sensors with a core,
where the current flows through a conductor which is enclosed by a
magnetic core with a high permeability.
A second type of current sensors comprises shunt current sensors,
where a voltage drop across a portion of a conductor, for example a
portion with a defined resistance, is measured when current flows
through it. Such a measurement often requires a galvanic coupling
of sensor circuit and measured current.
With both of the aboves types, a conductor portion where the
current is measured may be integrated with the sensor or external
to the sensor (for example a wire passing through a ring core).
Current sensors, in particular conductor portions thereof through
which the current to be measured flows, have been increasingly
miniaturized in recent years. For example, a miniaturization of the
conductor portion along a direction of current flow in some cases
may serve to reduce power dissipation and generation of heat by the
dissipated power. However, such a miniaturization may lead to
inaccuracies or measurement errors, as a geometry of the
surroundings of the current sensor and in particular a contact
geometry may affect the measurement to a greater extent than for
larger current sensors. This in particular applies to current
sensors where the conductor is integrated with the current
sensor.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram illustrating a current sensor device
according to an embodiment.
FIG. 2 is a flowchart illustrating a method according to an
embodiment.
FIG. 3 is a diagram illustrating a configuration and environment of
a current sensor device according to an embodiment.
FIG. 4 illustrates a current sensor device according to an
embodiment.
FIGS. 5A-5C show various schematic perspective views of a current
sensor device according to an embodiment.
FIG. 6 shows a schematic cross-sectional view of a current sensor
device according to an embodiment.
DETAILED DESCRIPTION
In the following, various embodiments will be described in detail
with reference to the attached drawings. It is to be noted that
these embodiments serve illustrative purposes only and are not to
be construed as limiting. For example, while embodiments are
described comprising a plurality of different details, features or
elements, in other embodiments some of these details, features or
elements may be omitted, may be implemented in a different manner
than shown, and/or may be replaced by alternative details, features
or elements. Additionally or alternatively, in other embodiments
additional details, features or elements not explicitly described
herein may be present. Connections or couplings, for example
electrical connections or couplings shown in the drawings or
described herein may be direct connections or indirect connections,
indirect connections being connections with one or more additional
intervening elements, as long as the general function of the
respective coupling or connection, for example to transmit a
certain kind of information in form of a signal, is maintained.
Furthermore, connections or couplings may be implemented as
wire-based connections or wireless connections unless specifically
noted otherwise.
Furthermore, details, features or elements from different
embodiments described herein or shown in the drawings may be
combined to form further embodiments unless specifically noted
otherwise.
In some embodiments, a current sensor device is provided. The
current sensor device may comprise a current sensing element to
sense a current through a conductor portion, for example a magnetic
current sensing element or a shunt-based current sensing element.
Furthermore, the current sensor device is adapted to obtain
information regarding a current path the current takes, e.g. a path
outside a conductor portion where the current is sensed, for
example information indicative of a direction of the current.
"Outside" the conductor portion may refer to one or more further
conductor portions outside a housing including the conductor
portion and the current sensing element, may refer to one or more
further conductor portions having a greater diameter than the
conductor portion, may refer to one or more further conductor
portions having a greater distance from the current sensing element
than the conductor portion, and/or may refer to one or more further
conductor portions outside contact points like solder spots
delimiting the conductor portion. In some embodiments, the
conductor portion may be made of one piece, for example a
structured metal piece. An output signal of the current sensor
device is generated based on a measurement of the current sensing
element and on the current path information. For example, the
current path information may determine a calibration factor or
other calibration or correction parameter applied to a measurement
output of the current sensing element.
In some embodiments, the current path information may for example
comprise a direction of a current flow. The current path
information may be received from an external element like a
controller, or may be obtained within the current sensor device,
for example based on a preliminary current measurement.
In other embodiments, other features may be provided. In still
other embodiments, corresponding methods may be provided.
Turning now to the Figures, in FIG. 1 a schematic block diagram
illustrating a current sensor device 10 according to an embodiment
is illustrated. While current sensor device 10 is depicted as
comprising four separate blocks, this is merely for illustrating
various functions performed within current sensor device 10 and is
not to be construed as indicating that the separate blocks have to
be implemented as physically separate portions or devices, but
merely indicates that the respective functionalities are provided
in the embodiment of FIG. 1. Generally, the functionalities
described with respect to current sensor device 10 may be
implemented in hardware, software, firmware or combinations
thereof, to give some examples.
Current sensor device 10 comprises a current sensing element 12
adapted to sense a current I flowing in a conductor portion 11.
Current sensing element 12 may for example comprise a magnetic
sensor element like a Hall sensor element or a magnetoresistive
element, for example a magnetoresistive element based on a giant
magnetoresistance (GMR) effect or a tunneling magnetoresistance
(TMR) effect. In other embodiments, current sensing element 12 may
be a shunt-based current sensing element measuring a voltage drop
over conductor 11 or part thereof, for example a part with a
defined resistance. Moreover, as indicated by 14 current sensor
device 10 receives a current path information, i.e. an information
regarding a way the current to be measured is flowing.
For example, the current path information may comprise information
regarding the direction of current flow, as indicated by an arrow
16 in FIG. 1. In other embodiments, the current path information
may comprise an estimated or roughly measured magnitude of the
current. In yet other embodiments, additionally or alternatively
the current path information may comprise information regarding a
direction from which the current enters conductor portion 11 and/or
in which the current leaves conductor portion 11. Other kinds of
current path information may also be provided.
The current path information in some embodiments may be obtained by
current sensor device 10 internally. For example, prior to
performing actual measurements, a preliminary measurement of the
current may be performed by current sensing element 12. Based on
this preliminary measurement, for example a direction (also
referred to as polarity) of current I may be obtained. Furthermore,
an approximation of the magnitude of current I may be obtained by
the preliminary measurement in some embodiments. In other
embodiments, additionally or alternatively current path information
14 may be obtained by an external source, for example a controller
15. Controller 15 may for example control switches directing
current paths through conductor portion 11. A state of such
switches may for example determine a direction of the current flow.
In such a case, corresponding information may be provided by
controller 15 to current sensor device 10.
In the embodiment of FIG. 1, a correction circuit 13 then generates
an output signal o indicative of the magnitude of current I based
on a measurement output of current sensing element 12 and on the
current path information. For example, in some embodiments
depending on the current path information different calibration
factors may be applied to a measurement signal from current sensing
element 12 to form output signal o. In other embodiments, for
example based on the current path information different bias
voltages or bias currents may be applied to current sensing element
12 to take the current path information into account. In other
embodiments, instead of a calibration factor, which may be close to
1, a correction value which may be small compared with the current
to be measured may be added to or subtracted from the measurement
signal from current sensing element 12. Such a correction or
calibration may be implemented in different ways, for example by
analog electronic means, by time continuous or time discrete
techniques like switched capacitors or by digital techniques or
combinations thereof. In some embodiments, a lookup table stored
e.g. in current sensor device 10, e.g. in a memory 17 thereof, may
be used, where for example depending on a polarity of the current I
and possibly also on an approximate magnitude of the current to be
measured a calibration value is read out of a stored table.
It should be noted that conductor portion 11 or part thereof where
current sensing element 12 measures the current may be part of the
current sensor device 10 itself in some embodiments, and the
representation in FIG. 1 where conductor portion 11 is on a side of
current sensor device 10 is only for ease of representation.
As mentioned above, in some embodiments the current path
information may also comprise information regarding a magnitude of
the current. In some embodiments, such an estimate or approximate
measurement of the magnitude may indicate a current path. For
example, in some embodiments a small current may be delivered only
via a single transistor acting for example as a switch, whereas
large currents may be delivered by a parallel connection of several
transistors. In embodiments, such transistors may have a
non-negligible size and may be positioned side by side for example
on a cooling plate like a direct copper bond board. In such a case
for example small currents may be carried by a transistor which is
close to current sensing element 12, whereas at larger current
portions of that currents are also carried by more distant
transistors. In such a case, correction circuit 13 of current
sensor device 10 may for example multiply a smaller current by a
larger factor, for example 1.03, whereas larger currents in the
same direction may be multiplied by a smaller factor, for example
1.01. These values and relations serve only explanatory purposes
and my be different in other embodiments. In practice they may
depend on an arrangement and size of elements of the respective
embodiment (such as conductor traces and power transistors used to
carry the current) as well as on their physical properties (e.g.
their on-resistance) and/or also on a thermal and transient
behavior of the embodiment. The values and relations can for
example be determined experimentally.
Generally, such embodiments use that in particular for small
current sensor devices and/or small current sensing elements the
current sensed may depend on the current path, for example due to
inhomogeneous field distributions at the current sensing element.
The influence of the current path is difficult to calibrate in
advance. For example, as explained current sensing element 12
measures the current flowing through conductor portion 16.
Conventionally, during or at an end of manufacturing device 10
device 10 is calibrated by means of conductor portion 11 or a test
conductor simulation conductor portion 11. In devices where
conductor portion 11 is part of device 10 and is contacted later
when incorporating device 10 in an application, for calibration for
example test tips or contact sockets (or other releasable contact
means) may be used for contacting device 10 in order to apply a
test current to conductor portion 11. Therefore, during such a
calibration contacting of device 10 differs from the contacting in
the later application, and such a calibration may only take into
account a standardized test environment, but not the real
environment where device 10 is used later. The real environment,
i.e. conduction paths to and from conductor portion 11 in the
actual implementation, influence the field distribution and
therefore the measurement results. This influence of the
environment in embodiments increases with decreasing length and
increasing diameter or width of conductor portion 11, as then
disturbing influences from the environment may be closer to
conductor portion 11 in embodiments. On the other hand, it is
desirable to decrease the length and increase the width or diameter
of conductor portion 11 to decrease ohmic resistance and therefore
heat dissipation. By using the correction by correction circuit 13
as explained above, in embodiments the influence of the environment
may be at least partially compensated, and conductor portions
having decreased length and/or increased width or diameter may be
used compared to conventional solutions while still maintaining a
required accuracy of a current sensing.
In FIG. 2, a flowchart illustrating a method according to an
embodiment is shown. While the method will be described as a series
of acts or events, it should be noted that the order in which the
acts or events are described is not to be construed as limiting. In
particular, in other embodiments other orders than the one shown
and described may be used, and/or acts or events described may be
performed parallel to each other, for example by different circuit
paths of a circuit.
At 20, the method of FIG. 2 comprises obtaining information about a
current path of a current to be measured. The information may for
example comprise a direction of the current and/or an estimate of a
magnitude of the current. In some embodiments, the current path
information may be obtained by a source external to a current
sensor device, for example controller 15 of FIG. 1. In other
embodiments, obtaining the current path information may be
performed within a current sensor device. For example, obtaining
the current path information may comprise performing a preliminary
current measurement, for example to obtain a polarity of the
current to be measured and/or an estimate of the magnitude of the
current.
At 21, the method comprises measuring the current, for example
using a shunt-based current sensing element or a magnetic field
based current sensing element.
At 22, the method comprises generating an output indicative of the
current measured based on the current path information and the
measured current. For example, in embodiments the current measured
at 21 may be multiplied with a calibration factor depending on the
current path information, or a correction value based on the
current path information may be added to the measured current.
Generally, the generation of the output may for example be
performed as already discussed with reference to FIG. 1 above.
The method of FIG. 2 may be implemented using the current sensor
device of FIG. 1, but may also be implemented using other devices.
Modifications, variants and details applicable to current sensor
device 10 in FIG. 1 may also be applicable to the method of FIG. 2
and vice versa.
Next, with reference to FIGS. 3-6 various implementation
possibilities for current sensing elements usable in current sensor
devices of embodiments as well as illustrative environments where
current sensor devices according to embodiments may be used will be
illustrated with reference to FIGS. 3-6.
In the embodiment of FIG. 3, a shunt current sensor device 312 is
used arranged between two current contacts 33, 34 to sense a
voltage between contacts 33, 34. Between contacts 33, 34 the
current may flow via a restricted passage 313, which in the
embodiment of FIG. 3 is arranged below current sensor device 312.
Shunt current sensor device 312 may generally be implemented as
discussed with reference to FIG. 1. Shunt current sensor device 312
in the example of FIG. 3 is arranged to sense a current flowing to
or from a load 37, which is coupled between current sensor device
312 and a load ground 38. 35 denotes sense inputs of current sensor
device 312. Elements denoted 39, for example load ground 38 or
ground terminal of the half-bridge 311, may be so-called current
traces on a printed circuit board (PCB) or some other kind of
component board which holds the current sensor and/or power
transistors and interconnect lines between them. The component
board in embodiments may also serve the purpose of delivering
dissipated heat, as it is for example the case in direct copper
bond (DCB) substrates or insulated metal substrates (IMS).
The arrangement of FIG. 3 corresponds to a half-bridge
configuration, where current may flow to load 37 via restricted
passage 313 from a positive supply terminal 30 of the half-bridge
configuration as indicated by an arrow 32. Current from positive
supply terminal 30 to load 37 is switched via a number of high-side
power transistors 31 in the embodiment of FIG. 3, three high-side
power transistors 31 being shown in the Figure. However, any
suitable number of power transistors may be used.
Current flowing from load 37 to restricted portion may ultimately
flow to a ground terminal 311 of the half-bridge via one or more
low-side power transistors 310, two of which are shown as an
example. As indicated by an arrow 314, the current path in this
direction differs from the current path indicated by arrow 32.
Therefore, depending on switching states of power transistors 31
and power transistors 310, the current path differs, and the
polarity differs. Therefore, in FIG. 3 the current may flow in
different branches depending on a polarity, as illustrated by
arrows 32, 314 in FIG. 3. Such different current paths may lead to
different responses in a current-sensing element of current sensor
device 12, i.e. different voltage drops between current contacts
33, 34, even if the magnitude of the current is the same. With the
above-explained corrections depending on current path information,
for example depending on a polarity, such differences may be taken
into account in embodiments to improve the accuracy of the
measurement.
High-side switches 31 and low-side switches 310 may for example be
controlled by a controller like controller 15 of FIG. 1, and such a
controller may then provide information regarding the current path
(for example low-side or high-side) to a current sensor device.
Similar situations with different current paths may for example
occur if a load is split in two parts, where one conducts currents
in a first direction and the other conducts currents in an opposite
direction, for example positive and negative currents. Such
situations may for example occur if the load is a rectifier
converting an alternating current or voltage into a direct current
or voltage: In this case diodes or transistors connect a positive
voltage to a positive terminal of a capacitor bank while other
diodes or transistors connect a negative voltage to a negative
terminal of a capacitor bank in some embodiments. Also in such a
case, an output current flows through different paths depending on
polarity.
The environment of FIG. 3 is an example where a geometry of
external current connections like current rails connected to the
current sensor device may influence the output of the current
sensor, in particular for miniaturized current sensors with small
dimensions and/or small restricted passages. In case of shunt-based
current sensors like current sensor device 312, different current
paths as shown may influence a potential distribution inside the
shunt. In case of magnetic field sensors, also the current flowing
through current paths external to the current sensor device
generate magnetic fields, which in particular for small current
sensor devices may significantly influence the measurement, as for
smaller sensor devices these external current paths may be closer
to a location where the sensing is performed.
Generally, in conventional solutions often a sensor is only
calibrated with respect to the "internal" conductor, i.e. a
conductor portion used for sensing which may be part of the current
sensor device itself In embodiments, with the techniques described
above also an influence of different external current paths, for
example current paths not being arranged along a single line as
shown in FIG. 3, may be taken into account.
In FIG. 4, a plan view of a shunt element based current sensor
device 410 according to an embodiment is shown, wherein 420', 422'
correspond to current contacts, and bond wires 420 and 422 are
current sense input supplying a voltage potential to a current
sensor device 410. 444, 446 and 448 are further terminals of
current sensor device 410 like supply voltage terminals or output
terminals which are coupled to device 410 via bond wires 450, 452
and 454, respectively. 46 and 461 may be parts of a lead frame
which are stamped off during manufacturing and not present in the
final product. In the implementation example of FIG. 4, a portion
400 of a lead frame has areas 400A, 400, 400C and two attachment
areas 404, 405 with respective attachments holes 404', 405' with
which the current sensor device of FIG. 4 may be mounted to an
apparatus where it is to be used. While not explicitly shown in
FIG. 4, area 400 may have a restricted portion below current sensor
device 410, similar to what is shown in FIG. 3. Current sensor
device 410, which may be implemented as illustrated in FIG. 1, may
be mounted to portion 400 with an electrically insulating adhesive.
462 denotes separation areas where lead frame portions 461, 46 may
be separated from the remaining structure. The area surrounded by a
box 430 may be encapsulated in a housing in some embodiments,
including a part of portion 400, i.e. a part of the conductor.
The implementation of a current sensor together with lead frame
elements shown in FIG. 4 is to be taken merely as an example, and
other implementations may also be used. Furthermore, as already
indicated instead of shunt-based current sensing elements also
magnetic current sensing elements may be used, for example also in
an environment as illustrated in FIG. 3.
Next, with reference to FIGS. 5 and 6 example for magnetic current
sensor devices will be discussed.
FIGS. 5A-5C show various perspective views of a magnetic current
sensor device according to embodiments. FIGS. 5A-5C essentially
show half of a magnetic current sensor, the other half would be
mirror-symmetric with respect to a plane which for example
corresponds to the plane where the elements 52, 53, 54 are visible
in FIG. 5A.
FIG. 5A shows components 51-54 enclosed in a mold 50, while FIGS.
5B and 5C show perspective views without mold 50.
51 denotes a conductor, for example a lead frame or other kind of
conductor, which has a constriction 51A serving as magnetic field
generation portion, e.g. a conductor portion where a magnetic field
to be sensed is generated. Providing the constriction may e.g.
increase a current density. On conductor 51 in the embodiment of
FIGS. 5A-5C a structured glass platelet 53 is mounted using an
adhesive 52. On glass platelet 53, which for example provides
electrical isolation, a silicon die 54 with components formed
therein for implementing a current sensor device, for example the
current sensor device illustrated with respect to FIG. 1, is
provided. For example, functionalities for correcting a sensed
current based on information regarding a current path may be
implemented by corresponding circuitry in semiconductor die 54.
Current sensing elements, for example magnetoresistive elements or
Hall elements, may be formed in or on silicon die 54, e.g. on one
or both sides of constriction 51A in case of Hall elements or
directly above constriction 51A in case of magnetoresistive
elements. Other implementations of current sensors and current
sensing elements may also be used.
In FIG. 6, a cross-sectional view of a current sensor device
according to an embodiment is shown. The current sensor device of
FIG. 6 is somewhat similar to the current sensor device of FIG. 5
and may be an example for a cross-section thereof 61 denotes a
conductor, like conductor 51 of FIGS. 5A-5C or any other conductor
or conductive element. 62 in the embodiment of FIG. 6 is a
structured glass platelet, similar to glass platelet 53 of FIG. 5,
which is mounted to conductor 61 via an adhesive 64. It should be
noted that glass platelet 62 or 53 is just one example of a
galvanic isolation between a sensor chip and a conductor and
numerous other kinds of isolation platelets (e.g. made of ceramic
or cellulose), coatings (e.g. imides), layers (e.g. oxides or
nitrides), foils (e.g. Kapton) could be used. Moreover the means
for galvanic isolation may also be absent without significant
effect in some embodiments. Furthermore, a semiconductor chip die
63 is mounted to structured glass platelet 62 using e.g. an
adhesive 65. Semiconductor chip die 63 may for example implement
functions as discussed above with reference to FIGS. 1 and 2.
Furthermore, magnetic sensor elements like Hall sensors or
magnetoresistive sensors may be formed in or on semiconductor chip
die 63. Semiconductor chip die 63 is coupled to one or more
terminals 66 via one or more bond wires 67. Terminals 66 may for
example serve as output terminals for outputting a signal
corresponding to the measured current, as supply terminals or as
terminals to receive current path information as explained above.
68 designates a mold compound, like mold 50 of FIG. 5. Other
implementations of magnetic field sensing based current sensor
devices may also be used. It should be noted that while current
sensors having an internal conductor formed associated therewith
have been discussed above with respect to FIGS. 3-6, also current
sensor devices without an own conductor, which may for example be
mounted to a conductor, may be used in embodiments. A current path
length through such an internal conductor may be 15 mm or less in
some embodiments, although other values may be used as well.
Calibration factors, corrective values or similar values as
mentioned above may be stored in a table. In some embodiments, such
values may be programmable, for example to be stored in an erasable
memory like an EEPROM memory, such that the calibration factors or
correction values may be calibrated and determined for a sensor
depending on its environment, for example by applying known test
currents. Generally, embodiments of current sensor devices may be
applicable in situations where currents may take different paths,
which may be indicated by different polarities, different
magnitudes or other properties of the currents which may be
determined within the magnetic field sensor device, or information
regarding the current path may be supplied externally, as explained
above.
A correction applied to the measured signal as mentioned above may
adjust the measured current for example by not more than 10% or not
more than 5%. Current sensor devices according to embodiments may
for example be adapted to measure currents of up to 20 A or more,
although other values may also be used.
It is to be emphasized again that the above embodiments serve
merely as examples, and techniques and concepts described herein
may also be implemented in other manners than explicitly described,
as evident to persons skilled in the art.
Various embodiments of systems, devices and methods have been
described herein. These embodiments are given only by way of
example and are not intended to limit the scope of the invention.
It should be appreciated, moreover, that the various features of
the embodiments that have been described may be combined in various
ways to produce numerous additional embodiments. Moreover, while
various materials, dimensions, shapes, configurations and
locations, etc. have been described for use with disclosed
embodiments, others besides those disclosed may be utilized without
exceeding the scope of embodiments.
Persons of ordinary skill in the relevant arts will recognize that
embodiments may comprise fewer features than illustrated in any
individual embodiment described above. The embodiments described
herein are not meant to be an exhaustive presentation of the ways
in which the various features may be combined. Accordingly, the
embodiments are not mutually exclusive combinations of features;
rather, embodiments can comprise a combination of different
individual features selected from different individual embodiments,
as understood by persons of ordinary skill in the art. Moreover,
elements described with respect to one embodiment can be
implemented in other embodiments even when not described in such
embodiments unless otherwise noted. Although a dependent claim may
refer in the claims to a specific combination with one or more
other claims, other embodiments can also include a combination of
the dependent claim with the subject matter of each other dependent
claim or a combination of one or more features with other dependent
or independent claims. Such combinations are proposed herein unless
it is stated that a specific combination is not intended.
Furthermore, it is intended also to include features of a claim in
any other independent claim even if this claim is not directly made
dependent to the independent claim.
For purposes of interpreting the claims, it is expressly intended
that the provisions of Section 112, sixth paragraph of 35 U.S.C.
are not to be invoked unless the specific terms "means for" or
"step for" are recited in a claim.
While the foregoing has been described in conjunction with
exemplary embodiment, it is understood that the term "exemplary" is
merely meant as an example, rather than the best or optimal.
Accordingly, the disclosure is intended to cover alternatives,
modifications and equivalents, which may be included within the
scope of the disclosure.
Although specific embodiments have been illustrated and described
herein, it will be appreciated by those of ordinary skill in the
art that a variety of alternate and/or equivalent implementations
may be substituted for the specific embodiments shown and described
without departing from the scope of the present disclosure. This
disclosure is intended to cover any adaptations or variations of
the specific embodiments discussed herein.
* * * * *